I've been thinking a lot about character development lately. And, no, it isn't a writing thing, it's an acting thing. The entire reason for a story is how the protagonist goes from Ground Zero to the Endgame. Onstage, you can use your whole body to signal the change/development, but in audiobooks all you have is your voice. And music bed, if you do that sort of thing, but I'm a purist. I want all the listener's attention on me and the world I paint with words, the inner universe.
First, you have to lucky enough to get an author who understands character development and has the ability to write a story that supports that understanding. That's the thing that I find hardest about choosing which work to audition for. If the author is really sloppy, you can tell that in the excerpt they choose for the audition, but the vast majority of writers look good one chapter at a time. I don't have the time to buy and read each book (though wouldn't that be a fine life!), so I tend to stick with known properties, authors I'm familiar with or have worked with. Many times I can't quantify what attracts me to a story; I am, as once was said about a young director I worked with, a visceral player.
There is one thing I have noticed about voicing a really well-crafted book: whether or not you sit down and sketch out each character's arc, the story leads you through it much more efficiently. In other words, I'm on the fence about character grids and copy scoring, because I've found my voice leads me away from them after I've found the meat in the character, the base design, the motivation, so to speak. And there are even times when a character talks through me and leads ME through the story. That's when it's really good.
Those are the properties you live for.
So, I guess the moral of this post is, listen to your own voice. If you've done your homework, it will reveal what you need to do.